Web applications (WAs) developed by companies are usually adapted to cover new business rules due to continuous changes in the organization requirements. Service Oriented Architectures (SOA) come to the scene to give a solution to these continuous changes providing a way to align business rules with underlying services. This is why there is a current trend to migrate legacy web applications to new SOAs. However, this migration requires the identification, publication and orchestration of the underlying service layer. These are complex tasks usually carried out ad hoc by manually defining and developing the service layer and its coordination. Moreover, these processes are usually performed at a low abstraction level, close to code, hindering reusability and maintainability of the obtained system. Model-Driven techniques aim at tackling the complexity of these processes since models drive the migration from a higher abstraction level. In that sense, this paper presents a Model-Driven systematic and semiautomatic process to modernize legacy WAs to SOAs. It also relies on techniques that are used to identify and classify the services offered by the different WAs of the organization. On the one hand, conceptual representations of the WAs and the service oriented architecture are obtained. On the other hand, the underlying services of the web applications are generated from models so that they may be offered as an interoperable service layer, which may be aligned with the company business rules and orchestrated with external services.